/Engine/Source/Runtime/GeometryCore/Public/Spatial/PointHashGrid3.h
Find all points in grid within a given sphere. Note: Not thread-safe to update, remove or insert points during this query.
the number of found points
int FindPointsInBall ( const [TVector](API\Runtime\Core\Math\TVector)< RealType > & QueryPoint, RealType Radius, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< RealType(const PointDataType &)> DistanceSqFunc, [TArray](API\Runtime\Core\Containers\TArray)< PointDataType > & ResultsOut, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< bool(const PointDataType &)> IgnoreFunc ) const